Internal-combustion engine



May s, 1928. 1,668,883

S. S. ALLWlLL INTERNAL COMBUSTION ENGINE Fil'ed Feb. 16', 1927 I 2 Sheets-Sheet 1 N May 8, 1928.

s. s. ALLWILL INTERNAL COMBUSTION ENGINE Filed Feb. 16. 1927 2 Sheets-Sheet 2 gwwmtoz dtephen Seymour AZZWZZZ thaw n is introduced betweenthe piston and the Patented May 8, 1928 UNITED STATES 1,668,883 PATENT OFFICE.

STEPHEN SEYMOUR ALLWILL, 0F AUCKLAND, NEW ZEALAND, iASSIGNOR. TO THE ALLWILL VARIABLE COMPRESSION ENGINE (30., LTD., 01 AUCKLAND, NEW ZEA- LAND, COMPANY OF NEW ZEALAND.

INTERNAL-COMBUSTION ENGINE.

Application filed February 16, 1927. Serial No. 168,710.

This invention has been devised in order to provide improvements in the construction of internal combustion engines, by the adoption of which, provision is made for the degree of compression of the explosive charges being automatically maintained at a constant, no matter what the volume of the charges drawn into the engine may be.

With these engines as at present constructed, the cubical area of the compression chamber in each cylinder remains the same throughout, so that when the throttle is fully open and full charges are being drawn'into such chamber, and the engine is running at full speed, the degree of compression of each charge reaches its maximum, while when thethrottle is partially closed and the charges drawnin are correspondingly reduced, the-degree of compression also is reduced. Thus the resultant power obtained by the expansion of the gases on each ex- I plosion is not as great as it should be, when running at slow speed, proportionately to the power obtained when running at high speeds, simply because the lessened degree of compression provides less expansive force on explosion.

The present invention has been devised with the object of overcoming this drawback and to provide that equal compression may be obtained automatically upon all variations of the charges, that is, a small charge will receive compression to the same de .gree as a large charge, and thus better power results are obtained.

The invention provides for this degree of compression being fixedito accord with the I nature of the oil fuel employed, as it is well known that the different grades of fuel give best'results when their resultant gases are compressed to certain degrees of compression. Thus for benzine, one degree of com pression may be fixed as the constant, for

alcohol, another, and so on. v

The invention may be carried out by providing each engine cylinder with a movable head arranged to move in and out within the cylinder, with relation to the travel of .the piston, so as to vary the area. of the 1 space betwen the piston and such head, and

loading the outer side of such head with 1 a suitable fluid pressure acting inwards 1 against the compression of the charge which head. This pressure is automatically con trolled to reach and-main the fixed constant.

The pressure on the outside of the movable head will tend to force it inward to a normal position with respect to the inward travel of the piston, which forms the minimum space required for the compression chamber of the cylinder. Then as the piston moves in on its compression stroke and the charge is compressed, the movable head will remain stationary while the compression on its inside increases to that on its outside, and then will move back as the pressure correspondingly increases, to enlarge the compression' chamber to hold the greater quantity and without increasing itspressure. Thus the head willmove automatically to ensure thatthe compression chamber area be varied to suit the different amounts of the explosion charges and to ensure the uniform compression thereof.

The said fluid pressure upon the outside of the movable head is obtained by the working of the engine itself.

Specifically, the invention has, for its object to provide a mechanical lock for the floating piston to securely lock the piston in its upper position or during the firing Still further objects will be apparent from the following specification, taken in connection with the accompany ng drawings 111 which like reference characters indicate corresponding parts throughout and .in

which, i v v Figure l is a vertical section of the engine- Fig. 2lisa top view of one of the cylin- 1 ders showing the brake ring and mechanism,

Fig; 3 is a topview of the brake ring,

, Fig, 4 is abottomview of the brake ring, Fig. 5 is a side view of the brake ring,

Fig.6 is a top view of the floating lock piston,

Fig. 7 is a bottom view of the floating lock piston,

Fig. 8 is a side view of the floating lock piston,

Fig. 9 is a cross section through the cylinder on the line 99 of Fig. 1, showing the teeth increased in thickness, and

Fig. 10 is a detail showing the teeth and double grooves in the cylinder wall.

The engine illustrated is a four cylinder four cycle engine having cylinders 1 to 4 with a. power piston 5 in each of them. Each cylinder comprises a cylinder wall 27 which is water jacketed, and an outer housing 34 surrounds the walls. The upper port-ion of the engine is provided with a cover 23 which closes the fluid chamber 32 extending over the entire top of the cylinders. Fluid pressure is maintained in the chamber by any suitable means which enters through pipe 35.

Each cylinder is provided with a floating piston which comprises two parts, the lower of which is the floating lock piston 9 and the upper is the floating brake ring 13. The

piston 9 may be provided with piston rings 10 to prevent leakage and it is provided with a shoulder comprising a tapered portion 11 which is adapted to seat on the shoulder 12 in the cylinder when the piston is in its lowermost position. Ports 6 may be provided in the portion 11 in order to provide a cushion efl'ect for the piston. The floating brake ring 13 comprises a groove 14 in its upper periphery in which a brake band 26 is provided having operating lugs 15. This band 26 is operated by means of alever 25 pivoted in the cylinder wall at 40 and which is adapted to actuateone of the lugs by means of a rod 41 secured to the lever. The lever is actuated by means of a cam projection 24 on the main cam 18, and the cams 18, one for. each floating piston, are mounted on'a shaft 22 which is'rotated by any suitable means such as a chain or gear wheels from the crank shaft of the engine.

The lower portion of the brake ring 13 and the upper portion of the lock piston 9 are provided with a plurality of grooves 42 on the outside thereof formed byteeth 43.

These grooves are cut into the sides of the piston and ring and are angularly arranged, and, as shown in Fig. 1, they are so arranged that they oppose one another. The cylinder walls of each cylinder are provided with two sets of teeth 17 formed by cutting the grooves 17 as clearly indicated in Fig. 10. These teethcooperate with the grooves 42 and it will be clearly seen from Fig. 1 that a reciprocating movement of the floating piston, that is the brake ring and the lock piston, will cause these parts to rotate in opposite directions, due to the opposed arrangement of the grooves 42. This operaeeaeea tion of the floating piston, when it is moved in its uppermost position, will cause the floating piston to become locked during the firing stroke of the engine, due to the fact that the cam 24 will contact with and actuate the lever 25, which will tighten the band 26 around the brake ring 13 to prevent rotation thereof. In this way a further upward movement of the floating piston can not take place, since, to allow it to do so, the brakering must rotate, due to the teeth and groove arrangement which cannot take place when the brake ring is gripped by the brake band 26. At the end of the firing stroke the cam 24 releases the lever and the cam 18 forces the brake ring 13 down on the lock piston 9, the latter of which being in the meantime forced again on its shoulder 12 when the pressure in the combustion chamber falls below that in the fluid chamber 32.

The floating pistons will be filled with a.

good quality of light lubricating oil to the level indicated by dotted line 31 and this is for the purpose of providing lubrication of the moving parts and for cooling. The space above'the oil level or that comprising the chamber 32 will be filled with air or other suitable fluid to a pressure of approximately 100 lbs. per sq. in. which is the pressure suitable, for instance, for ordinary gasoline. Fig. 1 shows the four cycles of operation of which 1 is the beginning of the firing stroke, 2 the compression stroke, 3 the exhaust stroke, and 4 the suction or intake stroke. In 1 the floating piston has receded away from the piston 5 to allow for the gas mixture between the two pistons. Since there is a pressure of say 100 lbs., for gasoline for instance, in chamber 32 and therefore on the floating piston the gas' mixture will ,be compressed to that pressure as any pressure over that amount will recede the piston, the displaced air taking the place of the piston which is moving downwardly, such as in 3. While the floating piston is moving upwards itis given a slight rotary motion, at thesame time forcing the brake ring upwards which is rotated in the opposite direction. Just at the moment of firlng the brake band will be tightened around the brake ring, due to the cam action which now takes place, and the brake ring 13 will be prevented from rotary 'motion and the floating piston is securely held in place, con-' sidering its upward movement, until the end of the firing stroke when the cam releases the brake band. The lock piston is now allowed to move, downward as the pressure in the combustion chamber decreases. Due to the upper open end of the brake ring 13, this member will not be forced down by the fluid pressure and therefore cam 18 is so cons'tr'ucted to force this ring down during the exhaust stroke. With the lock piston on its seat or shoulder 12 the piston 5, will, on

tion.

exhaust, reach to within of an inch of the lock piston 9 .so that all of the burnt gases will be forced from the combustion chamber. The floating piston will remain on itsseat during the intake stroke and for a portion of the compression stroke until the pressure in the combustion chamber exceeds the pressure in the chamber 32.

In a four cylinder four cycle engine three floating pistons will be seated at one time, while the fourth will be inits raisedposi- For firing the compressed gases a spark plug may be inserted in the side of the cylinder, as indicated by 29. The inlet and exhaust ports may be located in the sides of the cylinders as at 47 and 48, which are suitably controlled by valves.

The brake band 26 may be placed in the cylinder wall, thereby eliminating the groove 14-. In this way the brake band will be stationary.

ll claim as-my invention 1. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge; and means in said cylinder and on said floating piston for mechanically locking said-floating piston in the cylinder during the firing stroke of the engine.

2. An internal combustion engine comprising a cyllnder; a power piston 1n said cylinder; a floating piston in said cylinder adapt-- ed to provide an approximately constant pressure of the compressed fuel charge, said floating piston provided with teeth and grooves; and means in said cylinder cooperating with said teeth and grooves for mechanically locking said floating piston in the cylinder during the firing stroke of the engine.

3. An internal combustion engine comprising a cylinder; :1 power piston in said cylinder; a floating piston in saidcylinder adapt ed to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of a brake ring and a lock piston; and means on said brake ring, lock piston and cylinder for mechanically locking said floating piston in the cylinder during the firing stroke of the engine.

4. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge,

said floating piston consisting of a brake ring and a lock piston; a plurality of projections on the inside wall of the cylinder; and means on said brake ring and lock piston cooperating With said projections for mechanically locking said floating piston in the cylinder during the firing stroke of the engine,

5. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of a brake ring and a lock piston; a brake mechanism for the brake ring; means for actuating said brake mechanism during the firing stroke of the engine; and means on said brake ring, lock piston and cylinder for supplying rotary motion to the lock piston and brake ring in opposite directions to each other upon reciprocation thereof, said brake mechanism when actuated preventing the brake ring from rotatirig thereby mechanically locking said floating piston in the cylinder during the firing stroke of the engine.

6. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapt ed to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of a brake ring and a lock piston; a brake mechanism for the brake ring; mechanism during the firing stroke of the engine; and means on said brake ring, lock piston andcylinder for supplying rotary mo tions to the lock piston and brake ring in opposite directions to each other upon reciprocation thereof, said brake mechanism when actuated preventing the brake ring from rotating thereby mechanically locking said floating piston in the cylinder during the firing stroke of the engine. f

7. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of a brake ring and a lock piston; a brake mechanism for the brake ring; a cam for actuating said brake mechanism during the firing stroke of the engine; a second cam for forcing the brake ring downwardly during the exhaust stroke of the engine; and means on said brake ring, lock piston and cylinder for supplying rotary motions to the lock piston and brake ring in opposite directions to each other upon reciprocation thereof, said brake mechanism a cam for actuating said brake ing the brake ring downwardly during the exhaust stroke of the engine; levers cooperating with the first-named cam for actuating said brake mechanism; and means on said brake ring, lock piston and cylinder for supplying rotary motions to the lock piston and brake ring in opposite directions to each other upon reciprocation thereof, said brake mechanism when actuated preventing the brake ring from rotating thereby mechanically locking said floating piston in the cylinder during the firing stroke of the engine.

9. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constantprcssure of the compressed fuel charge, said floating piston consisting of two parts each having a plurality of inclined grooves therein; and means on one of said parts of the floating piston and on the wall of the cylinder for mechanically locking said floating piston in the cylinder during the firing stroke of the engine.

10. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of two parts each having a plurality of inclined grooves therein; a plurality of teeth on the wall of the cylinder cooperating with the grooves in the two two parts of the floating piston to impart rotary motions to the parts in opposite directions to each other upon reciprocation of the floating piston; and means for preventing rotation of one of the parts of the floating piston for mechanicall locking said floating piston during the firlng stroke of the engine.

11. An internal combustion engine comprising a cylinder; a'power piston in said cylinder; a float-ing piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of two parts each having a plurality of inclined grooves therein; a plurality of teeth on the wall of stant pressure of the compressed fuel charge, said floating piston consisting of a brake ring and a lock piston each having a plumesses rality of inclined grooves therein which are inclined in opposite directions from each other; and means on the brake ring and on the wall ofthe cylinder for mechanically locking'said floating piston in the cylinder during the firing stroke of the engine.

13. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge, said floating piston consistin of a brake ring and a lock piston each aving a plurality of inclined grooves therein which are inclined in opposite directions from each other; a plurality of teeth oil the wall 'of the cylinder cooperating with the grooves of the lock piston and brake ring to impart rotary motions thereto in opposite directions from each other upon reciprocation; and means on the brake ring for preventing rotation thereof to mechanically lock said floating piston in the cylinder during the firingstroke of the engine.

14. An internal combustion engine comprising a cylinder; a power piston in said cylinder; a floating piston in said cylinder adapted to provide 'anapproximately constant pressure of the compressed fuel charge, said floating piston consistin of abrake ring and a lock piston each 1% rality of inclined grooves therein which are inclined in opposite directions from each other; a plurality of teeth on the wall of the cylinder cooperating with the grooves of the lock piston and brake ring to impart rotary motions thereto in opposite directions from each other upon reciprocation; a brake mechanism on the brake ring for preventing rotation thereof and means for actuating said mechanism during the firing stroke of the engine to mechanically lock the floating piston in the cylinder.

15. An internal combustion engine comprising a cylinder; a power piston in said.

cylinder; a floating piston in said cylinder adapted to provide an approximately constant pressure of the compressed fuel charge, said floating piston consisting of a brake ring and a lock piston each having a plurality of inclined grooves therein which are inclined in opposite directions from each other; a plurality of teeth on the wall of the cylinder cooperating with the grooves of the lock piston and brakering to impart rotary motions thereto in opposite directions from each other upon reciprocation; a brake mechanism on the brake ring for preventing rotation thereof; and a cam for actuating said mechanism during the firing stroke of the engine to mechanically lock the floating piston in the cylinder.

aving a plu- In testimony whereof I afiix mysignature. I

S PHEN SEYMOUR ALLWILL. 

